文摘
An inherent problem stalling the development of a H2-based global energy economy is the unavailability of efficient functional catalysts that can function in aqueous media. A Fe鈥揊e hydrogenase mimic is investigated for electrocatalytic hydrogen generation in aqueous medium. H2 is produced from acid water (pH <3) by a Fe鈥揊e hydrogenase mimic immobilized on graphite surfaces. These catalysts are known to reduce H+ at very negative potentials in organic solvents. However, in aqueous medium, the H+ reduction potential is shifted to much more positive values. The catalyst shows a turnover frequency of 6400 s鈥? at 鈭?.5 V and an onset potential of 鈭?.36 V vs NHE. Prolonged electrolysis shows that the catalyst has a turnover number 108 and a Faradaic efficiency > 95%. Even at pH 2, that is, [H]+ = 0.01 N, Icat/[蟿] > 400 s鈥? is obtained. The catalyst can be immobilized on cheap carbon electrodes, used in domestic Zn-Carbon dry batteries, to generate H2 from acid aqueous solutions.
Keywords:
hydrogen evolution reaction; iron hydrogenase; bio-inspired catalysis